With the improvement of standard of living, urban traffic already becomes increasingly congested. In order to solve the current situation of urban traffic congestion, with the development of railway traffic industry, the light rail is already gradually used in construction of each large city, the vehicle coupler serving as a necessary component for connecting a vehicle plays an important decomposing and coupling role in the railway transport process, and most of the conventional semi-permanent vehicles coupler with or without buffers are directly and fixedly arranged on vehicle bodies through mounting seats; and when decomposition is needed in loading and maintenance or other conditions, the mounting seats or coupler yoke keys must be detached, and the detachment is inconvenient. Meanwhile, a buffer with good conformability with the light rail needs designing.